I am going to get a piece of aluminum and change the plastic pieces behind the earpads. There is coloration and I think it is because of making these pieces out of plastic. Everything else is so open
that I can't think of anywhere else that would cause coloration. I know that the Sigma's are totally insulated and I tried them like that but I do hear quite an improvement having them somewhat open
behind the ear. Is the 407 and the 507 the same drivers?
The plastic I had behind the earpads was a big problem. I took me a good while to make new pieces out of quarter inch aluminum but it was necessary. The plastic was flexing and coloring the sound
really bad. That is why I found improvement by opening up some insulation in the back. Now I have them insulated the way they should be and the sound is pretty good. They are very solid even though
they are very open and that plays a very important part on the overall sound quality in my opinion.
Edited by jaycalgary - 3/18/11 at 10:57pm